sedimentary
Flint
SiO2 (Microcrystalline Quartz / Chert)
Hardness of 7 on the Mohs scale, typically gray, black, or dark brown in color, waxy to vitreous luster, cryptocrystalline or microcrystalline structure, conchoidal fracture with no cleavage, specific gravity of 2.60 to 2.65
Identified More sedimentary →
Explore Flint in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 7 on the Mohs scale, typically gray, black, or dark brown in color, waxy to vitreous luster, cryptocrystalline or microcrystalline structure, conchoidal fracture with no cleavage, specific gravity of 2.60 to 2.65
Formation & geological history
Forms as nodules in sedimentary rocks such as chalk and limestone through the replacement of calcium carbonate by silica-rich solutions in marine environments over millions of years
Uses & applications
Historically used for making stone tools, arrowheads, and striking fire; currently used in abrasives, ceramics, and occasionally as a decorative or ornamental stone
Geological facts
Flint was one of the earliest materials manipulated by early humans for weaponry and tools due to its sharp conchoidal fracture edges
Field identification & locations
Found worldwide within chalk and limestone formations, easily identified by its smooth weathered cortex, waxy luster on fractured surfaces, and ability to spark when struck with steel
More like this
Other sedimentary specimens
Sandstone or Siltstone
Arenite (if sandstone)
Sedimentary
Sedimentary Sandstone
Arenite (Sedimentary Rock)
sedimentary
Fossiliferous Concretion
Septarian Concretion containing Brachiopods/Crinoids
fossil
Banded Siltstone / Mudstone Pebble
Siltstone / Argillite
sedimentary
Shale (or Mudstone/Siltstone)
Sedimentary Mudrock (SiO2, Al2O3 base with clay minerals)
sedimentary
Shale
Shale (clastic sedimentary rock)
sedimentary